Efficacy of native entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) against Helicoverpa armigera (Hübner, 1808) (Lepidoptera: Noctuidae)

Authors : Abdurrahman Sami Koca

Pages : 451-475

Doi:10.16970/entoted.1595065

View : 51 | Download : 62

Publication Date : 2025-01-21

Article Type : Research Paper

Abstract :Helicoverpa armigera (Hübner, 1808) (Lepidoptera: Noctuidae) is a significant agricultural pest with resistance to conventional synthetic insecticides. The present study, conducted in 2024 at Bolu Abant Izzet Baysal University, Biological Control Laboratory, investigated the pathogenicity of Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) against six larval stages of H. armigera. Three conidial concentrations (1×10⁶, 1×10⁷, and 1×10⁸ conidia ml⁻¹) were evaluated. This study analyzed the effects of varying spore concentrations of B. bassiana on the mortality of H. armigera larvae, considering days post-application, dose, and larval stage. Lethal concentrations (LC50 and LC90) and lethal time values (LT50 and LT90) were calculated using probit analysis. Mortality increased with dose and was highest in early instars, particularly at 1×10⁸ conidia ml⁻¹, where LT₅₀ and LT₉₀ values for first instars were 4.05 and 8.10 days, respectively. Older instars exhibited lower mortality rates. LC₅₀ and LC₉₀ decreased with increasing concentrations, achieving 100% mortality in the first and second instars across all doses. Third instars displayed dose-dependent mortality, with LC₅₀ and LC₉₀ values of 6.88×10⁸ and 1.94×10⁴ conidia ml⁻¹, respectively. Higher spore concentrations reduced LT₅₀ and LT₉₀, enhancing mortality rates in younger larvae. These findings underscore the efficacy of B. bassiana against early larval stages, emphasizing the importance of application timing for effective biological control and its potential role in integrated pest management strategies.
Keywords : Beauveria bassiana, biyolojik mücadele, biyopestisit, entomopatojen fungus, Helicoverpa armigera